[jdowne04]

Do you guys think buying a Modi 3 and Magni Heresy would be a worthy upgrade from the Objective 2+Odac Rev b? I would be using these with mostly AKG cans such as the K712 Pro and K7XX

 

[raoultrifan]

Modi 3 and Heresy are newer and both measure very well, especially the Heresy that also has a bigger output power.
However, for the AKG headphones you are using I don't think in an A/B test, conducted correctly, you will hear any differences.

 

[matti621]

The O2 is the worst sounding amp I listened to. Is that your impression as well? Which amps did you contrast it with and liked better at the same price class? I had a $90 Chinese HA5000 clone which sounded a lot better.

 

[raoultrifan]

The O2 is the worst sounding amp I listened to.

Either your O2 is broken, either you never read real reviews and measurements that prove that this headamp is a very good one. It has a SINAD higher than 100dB, so it's completely transparent and it works with a huge amount of headphones. Check diyaudio forum for more technical details, but also for the measurements and thoughts on neurochrome webpage.

P.S.: A bad amp is the one who introduces unwanted harmonics and SINAD is below 90dB or it has treble or bass roll-off etc.

 

[descloud]

The O2 is the worst sounding amp I listened to. Is that your impression as well? Which amps did you contrast it with and liked better at the same price class? I had a $90 Chinese HA5000 clone which sounded a lot better.

I'd agree with raoultrifan's comments. I see one of the possible scenarios with what you're experiencing:

• Your O2 is defective, introducing unwanted distortion, channel imbalance, or artifacts in the record you're listening to
• Your source or DAC is not transparent and does not output the necessary voltage to reach the volume you're adjusting with the O2 amp - introducing distortion to the songs you're listening to
• You don't like how the HD600 reveals certain parts of a recording since the O2 amp is transparent - causing you to blame the amp for being transparent about your source
• You're sensitive to certain frequencies that the HD600's frequency response generates which the O2 amp (a transparent amp) reveals - causing you to describe how the amp sounds the "worst"

So either you have a defective unit, your DAC/source is the weak link of being non-transparent and terrible performing objectively, or you just don't like a transparent amplifier output.

 

[matti621]

I'd agree with raoultrifan's comments. I see one of the possible scenarios with what you're experiencing:

• Your O2 is defective, introducing unwanted distortion, channel imbalance, or artifacts in the record you're listening to
• Your source or DAC is not transparent and does not output the necessary voltage to reach the volume you're adjusting with the O2 amp - introducing distortion to the songs you're listening to
• You don't like how the HD600 reveals certain parts of a recording since the O2 amp is transparent - causing you to blame the amp for being transparent about your source
• You're sensitive to certain frequencies that the HD600's frequency response generates which the O2 amp (a transparent amp) reveals - causing you to describe how the amp sounds the "worst"

So either you have a defective unit, your DAC/source is the weak link of being non-transparent and terrible performing objectively, or you just don't like a transparent amplifier output.

If the O2 was defective or the cans had a peak I'd be able to tell from listening to test recordings and AB'ing.
I'd agree with you the O2 transparency was at fault if I didn't own a very transparent very analytical set - Dac1->T1.
It also wouldn't make sense the BHC sounded so much better despite measuring very well as well.

 

[adydula]

Sounding better is a very subjective topic....

 

[439598]

The O2 is the worst sounding amp I listened to. Is that your impression as well? Which amps did you contrast it with and liked better at the same price class? I had a $90 Chinese HA5000 clone which sounded a lot better.

yes, I have not found a better example of ''measures good, sounds bad'' than O2 Amp.
With modifications, like bypassing NJM2068 gain stage completely and replacing NJM4556 with OPA1622, the sound can be improved somewhat, and it should measure better, not worse, if done right. Unfortunately the power supply is also to blame for the poor sound quality... you'd basically be scrapping the entire original design to get something decent sounding.
If that HA5000 clone is really class A then any Class AB buffer like these op amps are not gonna sound great in comparison.

It's ironic that the Objective2 of all amps is the one that causes most people to realise measurements (at least the current methodology) cant tell full picture of the way something will sound.
And it's confusing that there are some many people who still believe its transparent, If you listen to at least one more amp that measures as well as or better than the O2 it should be obvious there is an audible difference in measurably transparent gear.

 

[adydula]

wow.....really?

 

[matti621]

yes, I have not found a better example of ''measures good, sounds bad'' than O2 Amp.
With modifications, like bypassing NJM2068 gain stage completely and replacing NJM4556 with OPA1622, the sound can be improved somewhat, and it should measure better, not worse, if done right. Unfortunately the power supply is also to blame for the poor sound quality... you'd basically be scrapping the entire original design to get something decent sounding.
If that HA5000 clone is really class A then any Class AB buffer like these op amps are not gonna sound great in comparison.

You put it a lot better than I ever could, I wish there was a way to give you 10 'likes' or at least buy you a beer.

It's ironic that the Objective2 of all amps is the one that causes most people to realise measurements (at least the current methodology) cant tell full picture of the way something will sound.
And it's confusing that there are some many people who still believe its transparent, If you listen to at least one more amp that measures as well as or better than the O2 it should be obvious there is an audible difference in measurably transparent gear.

I sometimes think nawguy or whatever was the creator's nickname started that project to double-irony troll the hi-fi community.

That said, which amp costing the same or less would you pick instead?

 

[adydula]

The idea was to NOT sound at all....

..and he did this to troll the retail overpriced audio manufacturers..

...your free to buy anyones stuff.

but the whole excercise was to produce a low cost, decent amp.

And thousands of folks bough, built and think differently...

All opinions and experiences are valid.

 

[Relaxasaurus]

I don't know guys I'm testing all of these and for the money the O2 is top notch.

For the naysayers what other amps at this price point where you thinking?

 

[matti621]

For the naysayers what other amps at this price point where you thinking?

Chinese brands. Some use the same Texas Instruments chips.

 

[adydula]

I have 20 head amps here...and doing blind testing....many folks have a real hard time identifying amps from one another...

When a person picks out the O2, and not the $600 amp they sometimes dont like this!!!

 

[adydula]

Lots of chi-fi stuff uses el crapo parts....